The present invention relates to a device for providing quick couplings for dental prostheses.
It is known that removable dental prostheses provided with appropriate couplings for quick anchoring to residual dental structures are currently available.
In particular, U.S. Pat. No. 5,030,094 discloses a quick coupling that ensures durable engagement and includes a spherical male element and a female element which is shaped complementarily with respect to said male element and is shaped like a sort of cap made of plastic material which is meant to be accommodated and stably retained in the removable part of the prosthesis.
Conveniently, the seat of said plastic cap is formed in a metal part which is meant to be monolithic with the removable part of the prosthesis. Said metal part is obtained preferably by lost-wax casting starting from a model, made of fettling, of the dental arch to be reconstructed.
The male element is instead supported by a pin made of metallic material which is prefabricated or obtained by casting from a calcinable plastic element. In prosthodontic couplings, said pin is threaded and is inserted and screwed in a tubular element which is meant to become monolithic with the fixed part of the prosthesis.
The male elements also act as locators for the correct assembly of the removable part of the prosthesis. However, considerable difficulties often occur during the manufacture of the prosthesis in ensuring the correct parallel arrangement of said male elements, as instead required for the optimum functionality of said prosthesis.
In order to ensure the correct parallel arrangement of the couplings, German Utility Model N. G 9309030.7 discloses a device for providing quick couplings for dental prostheses which comprises a substantially spherical male element which is meant to become monolithic with a removable part of the prosthesis and is suitable to couple with a female element which is shaped complementarily to said male element and is correspondingly provided by a fixed part of the prosthesis.
By virtue of the coupling, which allows a certain degree of rotation of the male element with respect to the female element, the pin can rotate through an angle with respect to the axis of the seat of said cap, so as to automatically find exact alignment with said cap.
However, if the couplings are not perfectly parallel the insertion of the male element in the corresponding female element can be difficult, with consequent difficulty in applying the dental prosthesis.